Discussion
RacerMike said:
As a word of warning, you'll probably need the ABS ECU off a DCT equipped M3 or a reflash of the existing one. It only needs to be the ECU which is held on by 4xM4 bolts, but without it, you'll probably find you get a 'DSC unavailable etc.' on the dash and no traction or DSC function.
There will be two separate calibrations for the DCT and manual 'boxes respectively with, at the very least, the different gear ratios in. With the calibration for a manual car in, you'll find that it will flag a plausability fault after driving a short distance as the wheel speed won't match what it's expecting from the powertrain.
If you've got a friendly dealer, they may be able to squirt the correct variant code software in to your existing ECU. Once that's done, it *should* retain all normal DSC function and, as is often the case with touring/estate cars, there won't be enough of a difference in dynamics for the calibration to require any different parameters over the saloon.
Thanks for the advice. My plan is to use a ABS/DSC unit from a DCT car so that everything is compatible and fingers crossed everything should in theory work as both the front and rear M3 axles will be swapped over with corresponding wheel sensors etc..There will be two separate calibrations for the DCT and manual 'boxes respectively with, at the very least, the different gear ratios in. With the calibration for a manual car in, you'll find that it will flag a plausability fault after driving a short distance as the wheel speed won't match what it's expecting from the powertrain.
If you've got a friendly dealer, they may be able to squirt the correct variant code software in to your existing ECU. Once that's done, it *should* retain all normal DSC function and, as is often the case with touring/estate cars, there won't be enough of a difference in dynamics for the calibration to require any different parameters over the saloon.
I will be using the complete body harness from an M3 DCT and will splice in the rear doors and tailgate function after I get things up and running first.
Hopefully this will keep the coding impact to a minimum although I don't think its going to be that simple.
Edited by E91M3 on Wednesday 13th February 19:34
E91M3 said:
RacerMike said:
As a word of warning, you'll probably need the ABS ECU off a DCT equipped M3 or a reflash of the existing one. It only needs to be the ECU which is held on by 4xM4 bolts, but without it, you'll probably find you get a 'DSC unavailable etc.' on the dash and no traction or DSC function.
There will be two separate calibrations for the DCT and manual 'boxes respectively with, at the very least, the different gear ratios in. With the calibration for a manual car in, you'll find that it will flag a plausability fault after driving a short distance as the wheel speed won't match what it's expecting from the powertrain.
If you've got a friendly dealer, they may be able to squirt the correct variant code software in to your existing ECU. Once that's done, it *should* retain all normal DSC function and, as is often the case with touring/estate cars, there won't be enough of a difference in dynamics for the calibration to require any different parameters over the saloon.
Thanks for the advice. My plan is to use a ABS/DSC unit from a DCT car so that everything is compatible and fingers crossed everything should in theory work as both the front and rear M3 axles will be swapped over with corresponding wheel sensors etc..There will be two separate calibrations for the DCT and manual 'boxes respectively with, at the very least, the different gear ratios in. With the calibration for a manual car in, you'll find that it will flag a plausability fault after driving a short distance as the wheel speed won't match what it's expecting from the powertrain.
If you've got a friendly dealer, they may be able to squirt the correct variant code software in to your existing ECU. Once that's done, it *should* retain all normal DSC function and, as is often the case with touring/estate cars, there won't be enough of a difference in dynamics for the calibration to require any different parameters over the saloon.
I will be using the complete body harness from an M3 DCT and will spice in the rear doors and tailgate function after I get things up and running first.
Hopefully this will keep the coding impact to a minimum although I don't think its going to be that simple.
martin mrt said:
You could use a loom from a DCT saloon, therefore only requiring the tailgate functions such as rear wash wipe/ window hatch to be enabled/spliced in? I'd think that would be easier than faffing with a coupe loom
I completely agree with you, however it's been hard enough trying to find E90 M3 parts let alone a complete loom! I've been studying the wiring diagrams for a while and the saloon and coupe are not a million miles apart. The obvious differences are the rear doors and the fact that the coupe has functions such as the seat belt assist which will need stripping away. The actual modules in the car (JBE and FRM etc..) are the same and the use of the BUS system reduces the amount of wiring involved.
E91M3 said:
Thanks for the advice. My plan is to use a ABS/DSC unit from a DCT car so that everything is compatible and fingers crossed everything should in theory work as both the front and rear M3 axles will be swapped over with corresponding wheel sensors etc..
I will be using the complete body harness from an M3 DCT and will spice in the rear doors and tailgate function after I get things up and running first.
Hopefully this will keep the coding impact to a minimum although I don't think its going to be that simple.
You should be fine then in terms of ABS. I doubt it is any different, but check the location of the sensor pack (yaw sensor and accelerometers which are sometimes refered to as the IMU) are in the same place between the cars.I will be using the complete body harness from an M3 DCT and will spice in the rear doors and tailgate function after I get things up and running first.
Hopefully this will keep the coding impact to a minimum although I don't think its going to be that simple.
As I said, there's usually such little difference between an estate and it's saloon sibling that it won't really affect the performance that much. If you can find one out of a saloon, it'd definitely be the best bet....although someone somewhere will have the service tools to re-flash the ABS with the correct software. It's a 30s job to do through the OBD.
martin mrt said:
I absolutely LOVE this, mores now its coming together
How much roughly do you estimate the build is going to cost? I would love to do one f these rather than "settle" for a saloon
I have not run through the spend to date yet, but I am probably way past a 5 figure sum (excluding base car).How much roughly do you estimate the build is going to cost? I would love to do one f these rather than "settle" for a saloon
I'll publish a parts list soon showing what needs to be swapped over as a reference so you can get an idea of what involved.
Thanks
Edited by E91M3 on Thursday 14th February 18:53
Edited by E91M3 on Thursday 14th February 18:56
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